docs: def membership_request_notifications(user):
      '''Notify user about pending membership requests'''
      orgs = [o for o in user.organizations if o.is_admin(user)]
      notifications = []
  
      for org in orgs:
          for request in org.pending_requests:
              notifications.append((request.created, {
                  'id': request.id,
                  'organization': org.id,
                  'user': {
                      'id': request.user.id,
                      'fullname': request.user.fullname,
                      'avatar': str(request.user.avatar)
                  }
              }))
  
      return notifications